The purpose of this Core is to provide a common set of state-of-the-art biochemical and[unreadable] genetic analyses to CIDAR researchers relevant to testing various hypotheses related to[unreadable] prediction of antidepressant response. The laboratories of the Core will provide assessments of[unreadable] hypothalamic-pituitary-adrenal (HPA) axis function, interleukin-6 and C-reactive protein (C-RP),[unreadable] antidepressant drug concentrations, and detailed genetic analyses. The latter includes fine[unreadable] mapping of candidate genes, choosing "tagging SNPs" as well as genetic data management.[unreadable] Particular emphasis will be placed on development of a dense polymorphism map for each[unreadable] candidate gene to identify the degree of linkage disequilibrium in different ethnic groups. These[unreadable] data will be provided to the statistical modeling core. Having these determinations performed by a[unreadable] central facility using a common set of high quality assay modalities will provide consistency across[unreadable] all of the subjects enrolled in this 5 year study.